1. Field of the Invention
The present invention relates generally to a composition and method for chemical vapor deposition formation of low k dielectric films.
2. Description of the Relater Art
In the field of semiconductor manufacturing, a need exists for low k organic polymer intermetal dielectrics that satisfy processing and performance criteria for sub-0.25 μm integrated circuit applications.
Currently, low k films are formed by spin-on processing using a high purity “lacquer,” comprising a polymer (e.g., polyarylethers or organosilicates) dissolved in a solvent medium, that is spin-coated onto a substrate. These lacquers are commonly referred to as spin-on solutions. Spin-on processes tend to be inefficient with poor material utilization.
Such spin-on solutions have a variety of associated problems, including manufacturability, conformality of the deposited material coating, purity and shelf life issues, and problems of achieving reproducibility of film thickness and performance characteristics.
Many of the problems associated with forming low k dielectric films from spin-on solutions are avoidable by use of chemical vapor deposition (CVD) to form the dielectric film material. The CVD process is readily controllable in an efficient and reproducible manner to produce deposited films of highly uniform thickness and useful physical performance properties. In addition, CVD-produced films are highly conformal in character, thereby avoiding the need for an edge bead removal process and a backside rinse process that is typically required when spin-on coatings of dielectric material are formed on a microelectronic device substrate.
Unfortunately, however, a very limited number of precursors exist for CVD formation of low k films. The polymers conventionally used in spin-on coating formulations are typically of large molecular weight, and non-volatile in character, rendering them wholly unsuitable for use in CVD processes.